(Caltrop or Creosote Bush family)

240 species in 25 genera are found in tropical and subtropical regions.

[Summary yet to be added]

Balanites Delile

Some authorities classify the genus in its own family, namely the Balanitaceae. It has also previously been classified in the Simaroubaceae.

Mechanical injury can result from these exceedingly spiny shrubs and trees of African bushland (Verdcourt & Trump 1969). The Masai of southern Africa used the thorns to pierce earlobes of children (Watt & Breyer-Brandwijk 1962).

Originally published as Balanites aegyptiaca, this species grows to form a small, spiny tree (UNESCO 1960). The spiny branches are used to fence cattle pens. Its spines may be 3 in [= 8 cm] long (Irvine 1961).

A toothpaste made of the bark caused erosive cheilitis. A patch test with the bark of the plant was negative, but strongly positive when mixed with the saliva of the patient (Strobel et al. 1978).

Phytochemical investigation of the bark has demonstrated the presence of the furanocoumarin bergapten (Seida et al. 1981). This renders the species potentially capable of inducing photoirritant dermatitis.

This species provides timber known as Maracaibo lignum-vitae or verawood. The sawdust of Guaiacum arboreum caused sneezing and was called in French pique-niz (Guibort 1849).

Guaiacum officinale L.

Lignum Vitae

This species yields lignum vitae wood from which is obtained the medicinal resin guaiacum. The heartwood has an aromatic and irritating taste. The wood is used to make bowling woods and brush-backs, etc. Frei (1932) described a case of dermatitis which began around a minor finger wound contaminated with lignum vitae sawdust, and spread to the hands and arms. Patch tests to the sawdust gave positive reactions negative to some other woods and in controls. A case of contact dermatitis from application of Tincture of Guaicum was reported by White (1897). Guaicol derived from guaiacum has irritant properties (Greenberg and Lester 1954). The resin of the wood yields guaiaretic acid. Sensitivity to nordihydroguaiaretic acid is noted under Larrea.

Guaiacum sanctum L.

Lignum Sanctum

This species has properties similar to those of Guaiacum officinale. Oil of Guaiac wood is derived from Bulnesia (Greenberg and Lester 1954).

Kallstroemia maxima Wight & Arn.

(syn. Tribulus maximus L.)

Greater Caltrop

In an investigation of "weed dermatitis" in the southern United States, positive patch test reactions to an extract of this plant were observed in three of 50 consecutive patients tested (Shelmire 1939).

A male developed dermatitis of the face, neck and hands a few hours after gathering the plant. A patch test to the leaf produced a positive reaction, negative in controls (Smith 1937). A man who was employed in preparing the wood for extraction of nordihydroguaiaretic acid developed dermatitis two weeks after he was first exposed (Weber 1953). Nordihydroguaiaretic acid, used as an antioxidant of fats, can cause allergic contact dermatitis (Jorgenson and Hjorth 1970, Hjorth and Roed-Petersen 1976).

This common native shrub of the deserts of the south-western United States is also cultivated. A gummy secretion makes the leaves look varnished and imparts a distinctive creosote-like odour, especially after rain. A tea is made from the root (Reemtsa and Maloney 1974).

Tribulus L.

Caltrop

20 species are found in tropical and subtropical regions.

The mericarps have sharp rigid spines which can stick into the foot of an animal. The name caltrop refers to the form of the fruit and indicates an iron ball armed with sharp prongs used on the battlefield in former times to impede cavalry horses. Centaurea is also known as caltrop.

Tribulus cistoides L.

This native weed of Hawaii, known as carpet weed since it covers large areas, can cause mechanical injury to the hands and feet (Pope 1968).

Tribulus pterophorus C. Presl

This species was listed by Steyn (1934) as a possible cause of tribulosis or geeldikkop in sheep. See Tribulus terrestris L. below.

Aplin (1976) notes that this species bears spiny fruit (burrs). The dried fruit is pernicious to the horse, for when the thorn enters the hoof, it completely rots the frog, crippling the horse (Maiden 1895). Gardner & Bennetts (1956) provide drawings of the ferociously spiny burr.

This plant is the cause of tribulosis or geeldikkop (literally, "yellow big-head") in sheep that have eaten the plant. Tribulosis is a photodermatitis (Steyn 1934, Watt & Breyer-Brandwijk 1962). The toxic principles of the plant cause liver damage and accumulation of phylloerythrin in the blood. Phylloerythrin, which is a breakdown product of chlorophyll, acts as a photosensitising agent. A suggestion of photodermatitis in man from the plant (Mathews 1937) lacks confirmation.

For homicidal purposes, the poisonous juice of Acokanthera venenata is smeared on a suitable prickly fruit such as that of Tribulus terrestris and strewn on a path which is likely to be used by the victim (Watt & Breyer-Brandwijk 1962).